View Issue Details
|ID||Project||Category||View Status||Date Submitted||Last Update|
|0003318||OpenFOAM||Bug||public||2019-07-25 08:10||2019-08-09 15:27|
|Fixed in Version|
|Summary||0003318: Strange behaviour of parcels with dynamic mesh in MPPICFoam|
|Description||I created this MPPICFoam case with dynamic mesh in which all particle forces are disabled and it's uncoupled ( coupled=false). When I run the case with linear oscillating motion parcels (nParticle=1) are moving in the opposite direction of the motion although they are supposed to stay still as there is no external force. This happens when packingModel or dampingModel is active. Same behaviour is observed even though there is only one parcel in the domain.|
I have attached the case and the videos in a tar file.
Moreover, when the gravity is on parcels stay still on the wall while the platform is moving as if there is no friction. The friction on the wall works well without these models; that is parcels move together with the platform.
I would appreciate if you could clarify this issue. Many thanks!
|Steps To Reproduce||Extract the zip file and run MPPICFoam|
|Tags||No tags attached.|
oscillatingMPPIC.tar.xz (2,019,988 bytes)
gravityOn.mp4 (183,919 bytes)
It seems that the MPPIC parcel and cloud don't support moving mesh. The packing and damping forces rely on a predictor-corrector scheme where the particle is moved, a velocity correction calculated, and then the particle moved again along the velocity correction. This correction move turns off forces and does some juggling of the time evolution (step-fraction and age), so that the correction doesn't affect the time-state of the particle. It's this bit that isn't right, and is causing the weird behaviour on moving meshes.
What it should do is move the particle, calculate the correction, go back to the origional position, then track again along the corrected velocity (as opposed to the velocity correction). That would work on both moving and stationary meshes. It would require more temporary storage or another (reverse) tracking step so that the particles can be returned to their original position.
Doing this would require signifcant effort. See https://openfoam.org/maintenance/ for details of how to fund such an undertaking.
For now I will put an error into MPPICCloud which triggers if the models in question are executed on a moving mesh.
I've added an error to both 7 and dev, so the issue is no longer reproducible.
Resolution of the actual issue is suspended, pending funding.
|2019-07-25 08:10||dscian||New Issue|
|2019-07-25 08:19||dscian||File Added: oscillatingMPPIC.tar.xz|
|2019-07-25 08:20||dscian||File Added: gravityOn.mp4|
|2019-08-09 14:39||will||Note Added: 0010665|
|2019-08-09 15:27||will||Assigned To||=> will|
|2019-08-09 15:27||will||Status||new => closed|
|2019-08-09 15:27||will||Resolution||open => suspended|
|2019-08-09 15:27||will||Note Added: 0010667|